三级固井技术在塔里木油田超深水平井中的应用

塔里木轮南侏罗三叠系油藏经多年开发后,压力降低,成为低压渗透层,压力系数1.15～1.18,钻井液密度超过1.2 g/cm3就会出现渗漏.完井技术套管裸眼段长,套管串与井壁间环空间隙小,循环阻力大,水泥浆密度高(平均在1.85～1.90 g/cm3),液柱压力大,固井施工泵压高,致使水泥浆在低压渗透的储集层段漏失,从而影响了固井质量,污染了油层,给完井后井下作业造成极大的难度.因此决定在国内率先采用三级固井技术试验并获得成功.

Application of triple cementing technique for ultra-deep horizontal wells in Tarimu Oilfield

After many years of production, Jurassic-Triassic reservoir in Lunnan of Tarimu becomes a low permeability layer with a pressure coefficient of 1. 15-1. 18. Leakage will happen once the drilling fluid density is more than 1. 20 g/cm~3. Because of problems such as long open hole completion casing length, small gap between casing string and hole wall, large circulation resistance, high slurry density (1. 85-1. 90 g/cm~3 in average), big liquid column pressure, high cementing pump pressure, leakage is easy to happen in low pressure section, which affects the cementing quality, pollutes the reservoir and leaves a great difficulty to downhole operation after the completion. Therefore, the development industry became the first domestic in using triple cementing technique and achieved success.